Prius Sales Tank Even With Higher Gas Prices

I have read that the accumulator indeed has a bladder. As for price, Peugeot has said 17k Euros IIRC.

This link also has a technical presentation pdf at the bottom of the page.

 

That works out at £13,500 which compares to the base price of their car at about £12,000. The Prius by contrast is £22,000.

 

Thermo losses can be close to nil, but that's why I say the efficiency depends on many considerations. In fact, every one of the efficiency factors you have mentioned has variables that make the efficiency also variable.

Considering the scenerio FPL gives us, where captured energy is stored overnight in a garage, the storage tank will seek to equalize temperature with the ambient air. Given the long duration of energy storage (sitting overnight), even a vacuum insulated container will give up a lot of energy while the air inside seeks to equalize temperature with the surrounding environment.

However, capturing the energy while braking for a stoplight, and then utilizing it right when the light turns green can result in high efficiency since we haven't given the compressed air much time to cool off. Fortunately this scenario is more typical of how an air engine would be used. The more stop and go driving that is encountered, the more efficient the hybrid will be in comparison to an ICE only vehicle.

A compressed air recovery system wouldn't be of much use on a continuous trip on the interstate where the brakes are not used... however, there is an interesting application for an air assisted motor even given this scenario.

ICE efficiency is not static, and depends greatly on how loaded the engine is. At low loads, such as maintaining a 55mph cruising speed on flat ground, an ICE is terribly inefficient. At higher loads, such as accelerating and climbing hills, the ICE becomes much more efficient.

This fact is the reason that the "pulse and glide" method of driving is more efficient than maintaining a constant speed. Since repeatedly accelerating up to speed and coasting down isn't a practical way to drive, a high efficiency air engine could be filled up during the "pulse phase" of engine operation, and then the stored energy could be released to maintain constant vehicle speed during the "glide phase". This allows the engine to work at it's high load, high efficiency range, yet still maintain constant velocity.

I would think a current gasoline engine paired with a high efficiency air engine could be capable of 100 MPG if it utilized the pulse and glide strategy.

This graph shows how a typical gasoline engine might be only 5% efficient at low loads, but 30% efficient at high loads. That is a 600% (not 25%) variance in efficiency just by presenting the same engine with different loads! Clearly the biggest gains to be made in petrol powered vehicles is operating the engine at the most efficient load.

 

Good luck holding a steady 70mpg on the 405 next to L. A. X. (and the surrounding 10 miles) during the morning & evening rush hours . It's often like driving through the Costco gas lines.
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